From the viewpoint of global environment protection, reduction of dependence on petroleum in relation to resources has been examined, and attention has been paid to various natural resources. Among polyamides, known as a product obtained from a raw material originating from natural products is polyamide 11. Polyamide 11 is produced by using, as a raw material, aminoundecylenic acid that is synthesized from ricinoleic acid, which is a main component of “castor oil” obtained from castor beans, through a number of processes.
Furthermore, as a component originating from natural products, rosin that can be collected from pine resin is available. This rosin is composed of a mixture of various terpene-based carboxylic acids; however, among those carboxylic acids, it is known that abietic acid is used for polymer materials (see, for example, JP-A No. 2008-274150 and JP-A No. 6-87946). JP-A No. 2008-274150 and JP-A No. 6-87946 disclose that abietic acid is used to modify the chain ends of a phenolic resin or an epoxy resin, thereby obtaining a rosin-modified phenolic resin and a rosin-modified epoxy acid resin, which are used as binders for coating materials and the like.